Electric meter



ci'.. 15, 1929. G, R, SHUCK 1,731,194]

ELECTRIC METER Filed March 17, 1927 2 Sheets-Sheet 2 /0/ 2 l 25" m1, 2f

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"Y: a Ill v INVENTOR f 6in/a Zi zzc ////////////////////////////////////77 3M v I# 5f /ZCK Mmm' Patented @cto 15, 1929i 1 STATES GORDON R. SHUCK, OF SEATTLE, WASHINGTON, ASSIGNOR TO DUNCAN ELECTRIC' MAN- UFACT'URING COMPANY, OF LA FAYETTE, INDIANA, A CORPORATION OF ILLINOIS ELECTRIC METER Application led March 17, 1927. Serial No. 176,108.

rlFhis invention relates to electric meters and, more especially, to a meter for recording` kilo-volt ampere-hours.

'lhe object of the invention, generally stated, is to produce a meter of this character which is of simple and durable construction, ei'iicient in operation, and capable of'measuring the energy of electric currents of either a single phase or a polyphase circuit.

More speciiic objects and advantages of the invention will appear in the following de scription.

The invention consists in the novel use within the lield of an electro-magnetic circuit ot a secondary electric-conducting body which is arranged to be moved by a loadcurrent operated device responsive to variations of load current in a manner to effect the rotation of a meter disk at a speed proportional to the product of volts and arnperes.

The invention is illustrated in the accompanying drawings, shown somewhat diagrammatically, in which,

Figure 1 is a plan view showing one embodiment of the invention; Fig. 2 is a front elevation thereof partly in vertical section; and Fig. 3 is a side elevation of the same and incltuling` the representation of a counter which is omitted from the other views. Fig. 41.-. is a plan view, partly in horizontal section, showing a modified form oi the invention; and Figs. 5 and 6 are front and side elevations, respectively, of the construction shown in Fig. ll. Fig 7 is a diagram--representing `graphically the relation between flux in a magnetic circuit and the voltage of a potential coil.

Referring to Figs. 1 to 3, inclusive, the reference numeral 10 represents mains connected to a source (not shown) of an alternats ing electric current and includes, in series, the winding of a load-current actuated device ot' known construction as, for example, a solenoid 23, as shown, and the potential coil 11 of an electromagnetic circuit. As shown, this electro-magnetic circuit comprises an iron core 12 of substantially the form of a letter C with an air-gap, which is indicated by 13.

into andfrom said air-gap, is a phasing plate or a shading coil 17 which may be ot any suitable shape, and as illustrated in Figs. 1 to 3 is represented as a rectangular frame having a stem 18. The stem 18 is provided with a series of rack teeth 19 engaging the teeth of a spur pinion 2O which latter is also in engagement with the rack teeth 21 provided upon the plunger 22 of the solenoid 23 above referred to. 25 represents a retractile spring connected to the plunger 22. 30 represents leads of a load circuit.

In operation, the potential coil 11 functions to set up an alternating magnetic iield in the magnetic circuit 12, substantially all of the flux passing through the meter disk 14 while but a part of the tiuxpasses through the shading coil 17. Assuming a constant potential, with a consequent unvarying magnitude of the magnetic field, the presence of the shading coil in the air-gap will cause such magnetic iield to shift in a manner to produce a torque with a consequent rotation of the disk. The lposition ot the shading coil in the magnetic lield, as will be understood, determines the magnitude of the torque which, in turn, determines the rotary speed of the disk. The position of the shading coil 17 in the magnetic field, however, is regulated by means of the series solenoid through the medium of the rack and pinion mechanism above described. At Zero current the solenoid is inert and the shading coil 17 is withdrawn (by the power of the spring 25) with respect to the magnetic iield, thereby reducing the torque until it is incapable of imparting movement to the disk.

But when a current passing through the series solenoid is increased, the solenoid is energized sufficiently to etfect movement to the shading coil into the magnetic field which will apply a rotary Jtorce to the meter disk.

This rotary force can be made proporlill) tional, or nearly so, to the current flowing in the series solenoid by a suitable motion transmissionmechanism, hence the speed of the disk is proportional to the current, assuming a constant magnitude of lthe magnetic field or a constant-potential.

Again, assuiniii'gany fixed Y'ci'urent'in the series solenoid, a change in the voltageof the 4potential coil 1 1 results in4 changing the flfds 'f'fQ-ffg'? fd' ff! in; CP aqueuse,'ihe'magnaade ef'thearqe with iespect to the disk. Moreover, at any s tationary position of the shading coil, the

speed of the disk may'be'madeiproportional to the voltage Within eomme reial limitsv of chang'-s'ay toa-ten per centincrease or decreasee-williehl is accomplished by operating the 'magnetic' circuit the properdensity.

-In 'order 'to explain'the Altermproper density?. v'reference l"is `-`had to "Fim v7 illustrating graphically the relation bet'ween'the flux in the l'magnet-ic "circuit A2 "an d rthe Vy'foltage o1 'the-"potential coil 1'1..Y Edenote's'the normal u (iperating 'Voltage -lo'f the meter; 'B, the fcrresponding nor'in'al flux, D, 'denotes a l() per cent decrease in 'vol-tage; A, the correcrease in-voltage ;"C,'the corresponding flux.

. 'The'torque, an'd'co'nsequently'the speed, of

the' metervv disk wfaries withfthe square of the flux, or nearly iso.' Therefore the magnetic 'circuitin tthe 'lj'areset'inventi'on operates at Y' such a density 'tliatalOpercenti'ncrease'and a. 10 per cent decrease ofvoltage will produce ,startsiteusfvaagts, has .geg-

jaar nie/meer disais weed eithernprtional "to'ithe current in the `vseries solenoid "the voltaige 4witlfal constant current, and,

of the `angle between the currentand voltage,I 'provide lan :electr-ic principles settori/th ,above with reference to the "meterf'shwn' in ligs, 1, an d 3. In the modified'forin, the c ore 122 of the magnetic circuit'isfprovided with a pole piece 121 which is mounted to A'rotate with a spindle 26 eigtenclingthrough the core as' indicated A:in` Figs. 5 ando. The polepieee 121, as

shown, of a substantially rectangular form 'and is slotted vfrom .below 'to f' provide bifurshad'ili'gcoil" 171 to carry" the latter in 'r'evoluble relation with respect to the axis of the spindle 26.

Rigid with said spindle 26 is a spur pinion 27 engaging rack teeth provided on the plunger 221 of a solenoid 231 in series with the mains l01. 251 represents a retractile spring'for the plunger 221.

A current in the series solenoid 231 will actuate the pinion 27 to rotate the pole piece y12 1tli e reby producing a tangential'component ottorque to eil'ect rotatory movement to the disk 14.

It is to be understood that when the currentin the seriessolenoid is zero the rotary p ositionoic the core section 121 is such as y.

'willproduce a substantially radially shift- Li'eld'lavii'ig no effective rotative torque.

In adjusting the shading coil it is desiiable toposition the same so that when the circuitcurrentis Zero, the shading coil will 1 produce'a'toifque .just` suiiicient to overcome the static'fiiction' of the disk spindle land the registeringmechanism which is operated by the disk, 'thus providing a no-load friction- CO'mpenSatin-g device which enables the disk to berea'di-ly. started with an expenditure of a minimum of current. Any suitable known 'devices may be utilized for locating the shading` c'oil'for friction-compensating as above "reerred'tm an example of which is illustratedinliigs. land 2, the same consisting in makingthecoil stein in two coinplemen- .tary parts-las 181 and 181-and adjustably uniting the same by means of a coupling sleeve 2liwhich is `connected with the stem parts by means of right and le'it hand screw threads,fso that by turning the sleeve in one rotary directionor the other the effective length oi' the stem maybe regulated.

"Furthermore, I expect to use in practice lf; "drag magnets'tnot shown) of known construetion'and operation as exemplified in an 'ordinary induction watt-hour meter, and likewise to employ any known type of counter or register device to be driven by the meter disk asin the ordinary watt-hour meter.

Shading coils rhave hitherto been employed in ra magnetic iield to produce a torque with respect to a meter 'disk to provide friction- Y'compensation `and light-load adjustment, as "in some induction' watt-hour meters.

Itis to vbe noted that the operative connections bet-ween the solenoid plunger and the shading'coil, as shown in the drawings, is for illustrative purposes only and not restrictive;

as, in practice, known means may advantageously be adopted to impart variable motion to the shading coil to ensure disk torque and disk speed proportional to the current, assuining a constant potential.

Vhile I have shown and described a solenoid as one 'means for moving the shading ycoil it is to be understood that it is shown for illustrative purposes only, as other known means may obviously be employed instead, so

lil() long as such means is capable of acting to move the shading coil responsive to changes in the load current of the circuit Whose energy is to be metered.

rlhe term shading coil or phasing plate as herein used is to be understood to include any electrically conducting member of such shape, size and characteristics as Will cause a magnetic field to shift back and forth in such a manner as to produce a torque for a meter disk.

What I claim, is,-

l. ln an integrating type alternating current meter, the combination of a potential coil, a magnetic circuit, Whose flux is produced by said potential coil, an air gap in said magnetic circuit, a metal disk free to rotate in said magnetic circuit, a shading coil also free to move in said air gap, and load current operated means for controlling movement of said shading coil, all cooperating to produce rotation of the disk directly proportional to the product of volts impressed on said potential coil and load current.

2. In an integrating type alternating current meter, the combination of a potential coil, a magnetic circuit, Whose flux is produced by .said potential coil, an air gap in said magnetic circuit, a shading coil also free to move in said air gap, a load current series solenoid operatively connected to said shading coil, all cooperating to produce a rotation of the disk directly proportional to the prod uct of the volts impressed in the potential coil, and the load current.

8. In an integrating type alternating current meter, the combination of a potential coil, a magnetic circuit linking With said potential coil, an air gap in said magnetic circuit, a metal disk free to rotate in said magnetic circuit, a shading coil also free to move in said air gap, load current operated means for controlling movement of said shading coil, adjustable means for changing the position of the shading coil at zero load current, all cooperating to perform two functions, one, rotation of the -disk proportional to the product of volts of said potential coil and load current, the second, to produce a torque on the disk at zero load current to overcome static friction.

Signed at Seattle, Washington, this 4th day of March, 1927.

GORDON R. SHUCK. 

